Some gas-fired cooktops include an ignition device to generate a spark to ignite a burner when applicable fuel valves are opened to deliver fuel to the burner. Other gas-fired cooktops utilize a ceramic hot surface igniter to ignite the burner. Rather than relying on a spark, a ceramic hot surface igniter includes an element that generates sufficient heat to ignite the gas supplied to the burner.
U.S. Pat. No. 7,148,454 to Chodacki et al. discloses a system for regulating voltage to an electrical resistance igniter. That system determines the line voltage supplied to the system and controls the voltage being applied to the electrical resistance igniters so a first voltage is applied initially and for a time period and thereafter a second voltage is applied, the second voltage being the operating voltage for the igniter.
U.S. Pat. No. 6,777,653 to Burkhart describes a controller for controlling an igniter, such as a silicon nitride hot surface igniter, by providing high frequency switching of full wave rectified alternating current across the igniter using a switching transistor in combination with a filter and a full wave rectifier bridge. The igniter controller may be tuned based upon the particular igniter in connection with which control is provided to allow for precise control of switching of power to the igniter. The full wave rectifier bridge is provided in connection with the switching transistor to provide high frequency switching of AC power across the igniter.
U.S. Pat. No. 5,951,276 to Jaeschke et al. describes an electrically enhanced hot surface igniter wherein an electronic control circuit is provided for a gas oven that includes a hot surface igniter that is heated through the application of electrical current to a temperature sufficient to ignite gas supplied through an electrically actuatable gas valve. The applied current is regulated by a micro-controller that controllably gates on a triac while taking into consideration a sensed current level.
U.S. Pat. No. 4,099,906 to Pinckaers describes a hot surface fuel ignition system including a special regulating type of transformer used to energize a hot surface igniter, a fuel valve and a fuse in a series circuit. The design of the regulating transformer provides an operating current in the igniter and valve that will not blow the fuse as long as the igniter is neither short-circuited nor heated to a level which would be destructive.
Each of these known systems provides a fairly complex electrical system for applying and controlling various voltage levels to hot surface igniters. Some of the systems also provide electronic coordination and control of the gas flow to automatically control the entire ignition process. Such systems may be considered to be overly complex and expensive to provide.
In view of these known concerns it would be advantageous to provide a simple switching system that can be manually operated concurrently with the operation of a gas valve to effectively provide ignition of the gas for appliances such as a cooktop.